Process of combining 4-dimethylamino-1-phenyl-2.3-dimethyl-5-pyrazolone with one of the esters of p. aminobenzoicacid and the products



Patented Oct. 4-, 1932 BAPTIST REUTER AND IVIATI-IILDE REUTER, F KRAILLING-PLANEGG, GERMANY PROCESS OF COMBINING 4-DIMETl-IYLAMINO-1-PHENYL-2.3-DIMETHYL-E-PYRAZOLONE WITH ONE OF THE ESTEIEZS 0F 1?. AMINOBENZOICAGID AND THE PRODUCTS No Drawing. Application filed April 12, 1930, Serial No. 443,910, and in Germany July 30, 1928.

Our invention is directed to new chemical products of very good therapeutical effect and to the process of manufacturing them, while combining 4-dimethylamino-l-phenyl- 2.3-dimethyl-5-pyrazolone with esters of the p. aminobenzoicacid, for example the ethylester and the isobutylester of said acid.

The new compounds are obtained by melting together 1 molecule l-dimethylamino-lphenyl 2.3 dimethyl 5 pyrazolone with 1 molecule of one of the esters of the aminobenzoicacid on the steambath. They may be ground after refrigeration or recrystallized from indifierent solvents.

We obtain the same compounds, while boiling a solution of 1 molecule -dimethylaminol-phenyl-2.3-dimethyl-5-pyrazolone with 1 molecule of one of the said esters in alcohol, ether, benzol and other indifierent organic liquids and cooling down after effected solution. The new products are obtained in white crystals and show sharp melting points.

Instead of crystallizing the solution it is also possible to evaporate in vacuo to dryness.

The new products are different from a mechanical mixture of both components. A mechanical mixture of the single components shows an unsharp melting point as described in the following examples.

(1) Product of 4 dimethylamino 1 phenyl-2.3-dimethyl-5-pyrazolone-p. aminobenzoicacidethylester. The new compound 4 dimethylamino 1 phenyl 2.3 dimethyl-5- pyrazolone and p. aminobenzoicacidethylester melts at -96 degrees (3., while a mechanical mixture melts from 82 until degrees C.

It is proved, that a new mechanical product is formed by the'following statement: The new product can be crystallized from indifferent liquids such as alcohol, ether and so forth in diiferent fractions and each fraction will show the unchanged melting point'of "14.1% N. corresponding to the formula 1 molecule 1-dimethylamino-1-phenyl-2.8-dimethyl-5-pyrazolone and 1 molecule p.

' aminobenzoicacidethylesterVexpressed by the formula C H O N while a mechanical mixture of both components 1 molecule to 1 molecule melts from 53-90 degrees C.

It is proved, that a new chemical product is formed by the following statement: The new product can be crystallized from indifferent liquids such as alcohol, ether and so forth in different fractions and each fraction will show the vunchanged melting point of 72-73 degrees C.

Tested by analysis those difierent fractions of crystallization show the same content of 13.2% N corresponding to the formula 1 mol ecule t-dimethylamino-l-phenyl-2.3-dimetln yl-5-pyrazolone and 1 molecule p. aminobenzoicacidisobutylester expressed by the formula C H O N Ether dissolves in. 100 parts only 5 parts of 4-dimethylamino-1- phenyl-2.3-dimethyl-5-pyrazolone, whereas it dissolves in 100 parts about 66 parts p. aminobenzoicacidisobutylesterQ- If a chemical compound Were not formed the different crystallizations from ether would show difi'erent melting points and different analytical values. The new products have compared with a mechanical mixture of both components certain advantages. v

A mechanical mixture has the properties of the separate components. d-dimethylamino- 1-phenyl-2.8-dimethyl 5 pyrazolone tastes very bitter, p. aminobenzoicacidethyl and isobutylester are of strong aneesthetical effect, so that a mechanical mixture of one of the esters with t-dimethylamino-l-phenyl- 2.3-dimethyl-5-pyrazolone would be refused If there would of 1 dimethylamino 1 Ether dissolves in 100 4 butylester is melting at 7243 degrees (1,

'15 degrees C. while stirring.

by many patients. Swallowing difficulties sometimes occur in the use of the mechanical mixtures. In the new products both properties, the bitter taste and strong anaesthetic efiect, are reduced to a minimum so, that they can be taken very easy by even sensitive people. The new compounds show a new therapeutical effect are analgesics and are useful in cases of rheumatism, colds, gastralgia, headache trouble etc.

Ewamples I. Preparation of the p. aminobenzoicacidethylester compound. (3 11 151 0 (1) 33 grams of the p. aminobenzoicacidethylester, and 46.2 grams 4l-dimethylamino- 1- henyl-2.3-dimethyl-5-pyrazolone are heated on the steam bath while stirring until all is liquid. This fusion is the new product and crystallizes in cooling down. The fusion may be used directly as it is after grinding. It is also possible to recrystallize the melting from indiilerent organic liquids.

The process may be illustrated by the following equation (2) 33 grams of p. aminobenzoicacidethylester and e62 grams l-dimethylamino-L phenyl-2.3--dimethyl-5-pyrazolone are heated on the steam loath with 10 grams of ethylalcohol for half an hour and cooled to about @ne obtains white crystals, which are separated and dried in vacuo. From the evaporated mother liquor more crystals are received by evaporating.

(3) 33 grams of ethylester of the p. aminobenzoicacid and 16.2 grams of e-dimethylamino l-phenyl 2.3 dimethyl 5 pyrazalone 1 are dissolved in alcohol and after boiling for hour the solution is evaporated in vacuo to dryness.

The new compound is soluble in alcohol, benzol, ether and shows the melting point 9596 degrees C.

II. Preparation of the p. aminobenzoie acidisobutylester compound. 0 11 0 1 (1) 19.3 grams of p. aminobenzoicacidisobutylester and 23.1 grams l-dimethylamino-1-phenyl-23-dimethyl 5 pyrazolone are 7 heated on the steam bath while stirring until all is liquid. This new fusion is the new product and cyrstallizes in cooling down.

This fusion may be used directly as it is after grinding.

It is also possible, to recrystallize the melting' from indifierent organic liquids.

The process may be illustrated by the following equation:

. O N (C1192 UH4.OOO.G4H9

(2) 10.3 grams of p. aminobenzoicacidisobutylester and 23.1 grams l-dimethylamino- '1-phenyl-2.3-di1nethyl-5-pyrazolone are heated on the steambath with 20 grams of ethylalcohol for half an hour and cooled to about The new compound is soluble in alcohol,

benzol, ether and shows the melting point 7273 degrees C.

Claims:

1. The process of making new compounds, of l-dimethylamino-1phenyl-2.3-dimethyl- 5-pyrazolone with p. aminobenzoic acid esters of the general formula:

oooR

wherein R stands for an alkyl radical, which process comprlses condensing one molecule of 4;- dimenthyl-amino-1-phenyl-2.3- dimethyl-5- pyrazolone with one molecule of a p. aminobenzoic acid ester, mixlng the said two compounds finest in'any way preferably in portion of one molecule to one molecule and heating up the mlxture until the reactlon is ended. 2. The process ofmaklng new compounds .oif -dimethylamino-1-phenyls23dimethyl -pyrazolone with p. aminobenzoie acid esters of the general formula:

wherein R stands for an alkyl radical, which process comprises condensing one molecule of 4 dimethylamino-l-phenyl-f2.3-dimethyl 5 pyrazolone with one molecule of a p. aminobenzoic acid ester, mixing finest preferably in proportions of one molecule to one molecule of the said two compounds by dissolving them in indifferent dissolving liquids and heating up to boiling for a while. I

3. As new products the compounds of the following formula:

as Q

mo-m \CZNEP- coon H3O :h-monm wherein R stands for an alkyl radical, forming White crystals which are readily soluble in alcohol, ether, benzol, toluol and other indifferent liquids of the same kind, hardly soluble in Water. 7

l. As a new product, the compound of the following formula:

melting from 95-96 degrees Celsius and forum ing white crystals which are readily soluble in alcohol, ether, benzol, toluol and other indifferent liquids of the same kind, hardly s01- uble in water.

In testimony whereof we aflix our signa- 'CUIGS.

BAPTIST REUTER. MATHILDE REUTER. 

